Xiph CELT/Opus decoder using libcelt.

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/libavcodec/libcelt_dec.c b/libavcodec/libcelt_dec.c
new file mode 100644
index 0000000000..3e52ab572e
--- /dev/null
+++ b/libavcodec/libcelt_dec.c
@@ -0,0 +1,134 @@
+/*
+ * Xiph CELT / Opus decoder using libcelt
+ * Copyright (c) 2011 Nicolas George
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <celt/celt.h>
+#include <celt/celt_header.h>
+#include "avcodec.h"
+#include "libavutil/intreadwrite.h"
+
+struct libcelt_context {
+    CELTMode *mode;
+    CELTDecoder *dec;
+    int frame_bytes;
+    int discard;
+};
+
+static int ff_celt_error_to_averror(int err)
+{
+    switch(err) {
+        case CELT_BAD_ARG:          return AVERROR(EINVAL);
+#ifdef CELT_BUFFER_TOO_SMALL
+        case CELT_BUFFER_TOO_SMALL: return AVERROR(ENOBUFS);
+#endif
+        case CELT_INTERNAL_ERROR:   return AVERROR(EFAULT);
+        case CELT_CORRUPTED_DATA:   return AVERROR_INVALIDDATA;
+        case CELT_UNIMPLEMENTED:    return AVERROR(ENOTSUP);
+        case CELT_INVALID_STATE:    return AVERROR(ENOTRECOVERABLE);
+        case CELT_ALLOC_FAIL:       return AVERROR(ENOMEM);
+        default:                    return AVERROR_UNKNOWN;
+    }
+}
+
+static int ff_celt_bitstream_version_hack(CELTMode *mode)
+{
+    CELTHeader header = { .version_id = 0 };
+    celt_header_init(&header, mode, 960, 2);
+    return header.version_id;
+}
+
+static av_cold int libcelt_dec_init(AVCodecContext *c)
+{
+    struct libcelt_context *celt = c->priv_data;
+    int err;
+
+    if (!c->channels || !c->frame_size ||
+        c->frame_size > INT_MAX / sizeof(int16_t) / c->channels)
+        return AVERROR(EINVAL);
+    celt->frame_bytes = c->frame_size * c->channels * sizeof(int16_t);
+    celt->mode = celt_mode_create(c->sample_rate, c->frame_size, &err);
+    if (!celt->mode)
+        return ff_celt_error_to_averror(err);
+    celt->dec = celt_decoder_create_custom(celt->mode, c->channels, &err);
+    if (!celt->dec) {
+        celt_mode_destroy(celt->mode);
+        return ff_celt_error_to_averror(err);
+    }
+    if (c->extradata_size >= 4) {
+        celt->discard = AV_RL32(c->extradata);
+        if (celt->discard < 0 || celt->discard >= c->frame_size) {
+            av_log(c, AV_LOG_WARNING,
+                   "Invalid overlap (%d), ignored.\n", celt->discard);
+            celt->discard = 0;
+        }
+        celt->discard *= c->channels * sizeof(int16_t);
+    }
+    if(c->extradata_size >= 8) {
+        unsigned version = AV_RL32(c->extradata + 4);
+        unsigned lib_version = ff_celt_bitstream_version_hack(celt->mode);
+        if (version != lib_version)
+            av_log(c, AV_LOG_WARNING,
+                   "CELT bitstream version 0x%x may be "
+                   "improperly decoded by libcelt for version 0x%x.\n",
+                   version, lib_version);
+    }
+    return 0;
+}
+
+static av_cold int libcelt_dec_close(AVCodecContext *c)
+{
+    struct libcelt_context *celt = c->priv_data;
+
+    celt_decoder_destroy(celt->dec);
+    celt_mode_destroy(celt->mode);
+    return 0;
+}
+
+static int libcelt_dec_decode(AVCodecContext *c, void *pcm, int *pcm_size,
+                              AVPacket *pkt)
+{
+    struct libcelt_context *celt = c->priv_data;
+    int err;
+
+    if (*pcm_size < celt->frame_bytes)
+        return AVERROR(ENOBUFS);
+    err = celt_decode(celt->dec, pkt->data, pkt->size, pcm, c->frame_size);
+    if (err < 0)
+        return ff_celt_error_to_averror(err);
+    *pcm_size = celt->frame_bytes;
+    if (celt->discard) {
+        *pcm_size = celt->frame_bytes - celt->discard;
+        memmove(pcm, (char *)pcm + celt->discard, *pcm_size);
+        celt->discard = 0;
+    }
+    return pkt->size;
+}
+
+AVCodec ff_libcelt_decoder = {
+    .name           = "libcelt",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_CELT,
+    .priv_data_size = sizeof(struct libcelt_context),
+    .init           = libcelt_dec_init,
+    .close          = libcelt_dec_close,
+    .decode         = libcelt_dec_decode,
+    .capabilities   = 0,
+    .long_name = NULL_IF_CONFIG_SMALL("Xiph CELT/Opus decoder using libcelt"),
+};